I am not certain what pen sold first.
My first show was in 1998-99. At that show I sold several dozen rollerballs (similar to the "cheapys" at CSUSA now), dressed in several types of wood and acrylic. Pricing was $35 to $48.
Wood was finished with spray lacquer or friction polish, acrylics and the "then current version of a tru-stone look alike" was sanded to 1500 grit and plastic polish.
There was another penmaker at that show, using ONLY diamondwood.
The "hobby-industry" was a lot different. Dick Sing was showing a big innovation, CORIAN!! AND he was drilling holes in it and filling with a contrasting color of CORIAN!!! Man, the SKY was the LIMIT!!